The FX-8350 is a very bad CPU for starsector additionally. It is worse than my current machine which i would never dare attempt 500 battle size on.
Specifically the 8350 is designed to really use all its cores together well. The problem is that many games and especially Starsector tend to rely on a single core. This is because the majority of the processing cannot easily (or at all) be temporally separated. Before calculating and asigning damage from attack 2 i must know whether or not attack 1 hit and did damage and how much. Everything must be done in sequence and so an extra core cannot add much value. Desiging games to take advantage of multiple cores is exceedingly difficult and Starsector does not really try.
For soecific benchmark info:
https://cpu.userbenchmark.com/AMD-FX-8350/Rating/1489As another example how this works in the current gen. The i5-9600k is about 5% slower in benchmarks(indistinguishable when overclocked) than the i9-9900k until you get to “full core speed” where the i9 is ~40% faster. But if you look at in game benchmarks the vast majority of games show basically no difference. Its only when doing the server(and not personal/gaming) oriented tests that the 9900 gets to the point where its advantages matter. But the 9900 is twice the price.
Your card was designed in the time when everyone thought that multi-core was going to revolutionize gaming. And it skimped on the single core power making it decidedly weak for non-workstation tasks.